A heat exchanger includes a core having a plurality of tubes and a plurality of fins stacked with one another. A heat exchanger may include side plates that are stacked with the core on both sides of the core. The side plates are disposed to mechanically reinforce the core.
Generally, heat exchanging performance of a heat exchanger is enhanced by increasing the number of pairs of a tube and a fin (hereinafter, “tube-fin pair”) of the core. However, the increase in the number of tube-fin pairs may lead to an increase in the size of the core in the stack direction of the tubes and the fins.